Nuclear-monitoring research at the Center for Seismic Studies. Rept. for 1 Oct 89-1 Oct 90

The research presented in this report covers activity by the research staff of the Center for Seismic Studies for the period between 1 October 1989 and 1 October 1990. The report is divided into five sections covering topics relevant to underground nuclear test monitoring of the Soviet Union. Data for these studies came from the Scandinavian arrays NORESS, ARCESS, and FINESA; the IRIS stations within the Soviet Union; and hand digitized records of Soviet underground nuclear explosions recorded at stations of the Soviet Seismic Network. A brief description of the contents of the report are given below. The first section is composed of two reports by Ryaboy that review Soviet literature focused on the seismic characteristics of the crust and upper-mantle near the IRIS stations in the Soviet Union. The first report discusses the crust and upper mantle velocity and Q structure beneath the stations, and the second discusses lateral heterogeneity of the upper mantle inferred from refraction data.